I have not found a bit which doesn't give you some delamination. I found some of the wood cutting bits to outperform the metal bits. Going slow till you scorred the glass layer helps. But what I always ended up doing is to drill a smaller hole and then use a Dremel to enlarge it at the ends. I used tapered pins with sandpaper then to enlarge the hole to the desired diameter in the wooden middle section, making sure that I only rotate the pin for sanding rather than moving it in and out.

Andreas

: hi all;
: on previous boats i've had trouble with the drill bit pulling the glass
: around the hole for the grab loops. i used just a regular metal cutting
: bit. what's the best type of bit to use to avoid the visable ring around
: the hole?
: tia
: daren.....